In a UMTS (Universal Mobile Telecommunications System) network, for the purposes of improving spectral efficiency and improving the data rates, system features based on W-CDMA (Wideband Code Division Multiple Access) are maximized by adopting HSDPA (High Speed Downlink Packet Access) and HSUPA (High Speed Uplink Packet Access). For this UMTS network, for the purposes of further increasing spectral efficiency and peak data rates, providing low delay and so on, long-term evolution (LTE) has been under study (Non Patent Literature 1). In LTE, as the multi access scheme different from W-CDMA, OFDMA (Orthogonal Frequency Division Multiple Access) is adopted on the downlink and SC-FDMA (Single Carrier Frequency Division Multiple Access) is adopted on the uplink.
In a third-generation system (W-CDMA), it is possible to achieve a transmission rate of maximum approximately 2 Mbps on the downlink by using a fixed band of approximately 5 MHz. Meanwhile, in the LTE system, it is possible to achieve a transmission rate of about maximum 300 Mbps on the downlink and about 75 Mbps on the uplink by using a variable band which ranges from 1.4 MHz to 20 MHz. Furthermore, in the UMTS network, for the purpose of achieving further improvement of spectral efficiency and peak data rates and so on, successor systems to LTE have been under study (such a system is called, for example, LTE Advanced or LTE Enhancement, and hereinafter, this system is referred to as LTE-A).
In LTE-A, for the purposes of further improving spectral efficiency and peak throughputs, allocation of a broader frequency band than that in LTE has been under study. And, in LTE-A (for example, Rel. 10), one of requirements is backward compatibility with LTE and a study has been made about adoption of a frequency band having a plurality of fundamental frequency blocks (component carriers: CCs) where the bandwidth of a fundamental frequency block can be also used in LTE.